Pipe traversing apparatus and methods

ABSTRACT

A robotic apparatus comprising first, second, and third wheel assemblies, and a clamping mechanism configured to apply a force for urging the second wheel and the third wheel to pivot in opposing directions towards a plane of the first wheel for securing the first wheel, the second wheel, and the third wheel to the pipe, each wheel assembly including an alignment mechanism for adjusting an orientation of the wheels to allow the robotic apparatus to move along a straight path or a helical path on the pipe. A method for navigating an obstacle on a pipe comprising advancing the robotic apparatus along a helical pathway on the pipe to position an open side of the robotic apparatus in longitudinal alignment with the obstacle, and advancing the robotic apparatus along a straight pathway on the pipe such that the obstacle passes unobstructed through the open side of the robotic apparatus.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation patent application of U.S.application Ser. No. 16/583,579, filed Sep. 26, 2019, which is acontinuation patent application of U.S. application Ser. No. 16/135,413,filed Sep. 19, 2018, now U.S. Pat. No. 10,465,835, granted Nov. 5, 2019,which claims the benefit of and priority to U.S. Provisional ApplicationNo. 62/560,265, filed Sep. 19, 2017, U.S. Provisional Application No.62/616,147, filed Jan. 11, 2018, and U.S. Provisional Application No.62/687,753, filed Jun. 20, 2018, all of which are hereby incorporatedherein by reference in its entirety for all purposes.

BACKGROUND

Many existing pipe crawling apparatuses are designed to either travelinside of pipes or are not equipped to travel around obstacles it mayencounter on the outside of pipes. In view of limitations of currenttechnologies, a need remains for pipe-crawling apparatus that areeffective in navigating around and/or over potential obstacles, e.g.,obstacles that present a change in the effective diameter of the pipe, achange in the effective curvature of the pipe, and/or obstacles thatprotrude from the pipe in one or more radial directions. Moreparticularly, pipe-crawling apparatus are needed that are effective innavigating around and/or over flanges, valves, tees, bends, supports andthe like. In addition, a need remains for pipe-crawling apparatus thatare effective in traveling relative to pipes without magnets, vacuum oraerodynamic forces. Additionally, a need remains for pipe-crawlingapparatus and associated systems that are effective in performingdesired functions relative to the pipe itself, e.g., corrosiondetection, wall thickness measurements, or based on travel along thepath but independent of the pipe itself, e.g., imaging and/or sensing oflocations accessible through travel along a pipe. These and other needsare advantageously satisfied by the apparatus and systems disclosedherein.

SUMMARY

The present disclosure is directed to a robotic apparatus for traversingthe outer surface a pipe or similar structure. The robotic apparatus, invarious embodiments, may comprise a first wheel assembly including awheel and an alignment mechanism, and configured for positioning on afirst side of a pipe; a second wheel assembly and a third wheelassembly, each including a wheel and an alignment mechanism, andconfigured for positioning on a second, opposing side of the pipe; and aclamping mechanism configured to apply a force for urging the secondwheel and the third wheel to pivot in opposing directions towards aplane of the first wheel for securing the first wheel, the second wheel,and the third wheel to the pipe, wherein the alignment mechanisms areconfigured for selectably adjusting an orientation of the wheels toallow the robotic apparatus to move along a straight path or a helicalpath on the pipe.

In various embodiments, at least one of the wheels may have a concaveshaped surface for engaging the pipe. At least one of the wheelassemblies, in various embodiments, may include a motor for rotating thewheel of the corresponding assembly. The motor, in an embodiment, may besituated inside of the wheel of the corresponding assembly.

The clamping mechanism, in various embodiments, may include one or morebiasing members for generating the pulling force. The one or morebiasing members, in some embodiments, may be configured to passivelygenerate the pulling force and may, in an embodiment, include at leastone of a tension spring, a compression spring, and a torsion spring. Theone or more biasing members, in some embodiments, may be configured toactively generate the pulling force.

The clamping mechanism, in various embodiments, may include a first armmember connecting the first wheel assembly with the second wheelassembly; a second arm member connecting the first wheel assembly withthe third wheel assembly; and one or more biasing members for applying apulling force to engage the wheels on opposing sides of the pipe, theone or more biasing members either connecting the first arm member tothe second arm member or connecting the first wheel assembly to thefirst arm member and to the second arm member. The clamping mechanism,in an embodiment, may further include a third arm member and a fourtharm member arranged parallel and adjacent to the first arm member andthe second arm member, respectively, thereby forming first and secondparallelogram-shaped linkages between the first wheel assembly and thesecond wheel assembly and between the first wheel assembly and the thirdwheel assembly, respectively, wherein the parallelogram-shaped linkagesmaintain the wheel assemblies in parallel alignment with one anotherregardless of a relative position of the wheel assemblies to oneanother.

The clamping mechanism, in various embodiments, may be offset from andparallel to a plane shared by the wheels. The robotic device, in variousembodiments, may include an open side situated opposite the clampingmechanism, through which an obstacle extending from the pipe may passunobstructed. The robotic apparatus, in various embodiments, may furtherinclude one or more members configured to extend across the open side ofthe robotic apparatus to prevent the robotic apparatus from falling offthe pipe. The one or more members, in some embodiments, may beconfigured to pivot along a plane of the open side to accommodatepassage of an obstacle through the open side of the robotic apparatus.

The alignment mechanism, in various embodiments, may be configured toadjust the orientation of a corresponding wheel in a rotationaldirection relative to an axis that is normal to the pipe. Adjusting theorientation of the wheels, in an embodiment, may cause the roboticapparatus to move along a helical path along the pipe. The alignmentmechanism, in various embodiments, may include a wheel frame to whichthe wheel is rotatably coupled about a first axis; a base plate to whichthe wheel frame is rotatably coupled about a second axis orthogonal tothe first axis; and a motor configured to rotate the wheel frame aboutthe second axis, thereby adjusting the orientation of the wheel relativeto the base plate.

The robotic apparatus, in various embodiments, may further include asensor assembly for inspecting the pipe or an environment surroundingthe pipe. The sensor assembly, in some embodiments, may include asensor, an arm member rotatably coupling the sensor to the roboticapparatus, and an actuator configured to rotate the arm member about therotatable coupling to move the sensor towards or away from the pipe.

In another aspect, the present disclosure is directed to a method fornavigating an obstacle on a pipe with a robotic apparatus. The method,in various embodiments may comprise the steps of providing a roboticapparatus comprising: (i) a first wheel configured for positioning on afirst side of the pipe, (ii) a second wheel and a third wheel configuredfor positioning on a second, opposing side of the pipe, and (iii) aclamping mechanism connecting the first wheel to the second and thirdwheels, and situated offset from and parallel to a plane shared by thewheels so as to define an open side situated opposite the clampingmechanism; advancing the robotic apparatus along a helical pathway onthe pipe to position the open side of the robotic apparatus inlongitudinal alignment with the obstacle on the pipe; and advancing therobotic apparatus along a straight pathway on the pipe such that theobstacle passes unobstructed through the open side of the roboticapparatus.

Advancing the robotic apparatus along a helical pathway, in variousembodiments, may include adjusting an orientation of at least one of thewheels rotationally relative to an axis that is normal to the pipe.Advancing the robotic apparatus along a straight pathway on the pipe, invarious embodiments, may include adjusting an orientation of the wheelsto be in alignment with a longitudinal axis of the pipe.

The robotic apparatus, in various embodiments, may include one or moremembers configured to extend across the open side of the roboticapparatus to prevent the robotic apparatus from falling off the pipe,wherein advancing the robotic apparatus along a straight pathway on thepipe such that the obstacle passes unobstructed through the open side ofthe robotic apparatus includes allowing the one or more members to pivotalong a plane of the open side to accommodate passage of the obstaclethrough the open side of the robotic apparatus. The method, in variousembodiments, may further include adjusting an orientation of two or moreof the wheels in opposing directions to advance the robotic apparatussideways relative to a longitudinal axis of the pipe and therebyreposition the robotic apparatus on the pipe to account for wheel slip.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative, non-limiting example embodiments will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings.

FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, and FIG. 1E illustrate variousobstacles that may be found along a piping system;

FIG. 2 is a perspective view of a robotic apparatus in accordance withan embodiment of the present disclosure;

FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D depict various views of a roboticapparatus in accordance with an embodiment of the present disclosure;

FIG. 4A is a cutaway view of an internal motor within a wheel inaccordance with an embodiment of the present disclosure;

FIG. 4B is a perspective view of a wheel assembly in accordance with anembodiment of the present disclosure;

FIG. 5A, FIG. 5B, and FIG. 5C depict various views of a roboticapparatus attached to a pipe in accordance with an embodiment of thepresent disclosure;

FIG. 6A and FIG. 6B depict a robotic apparatus on a smaller diameterpipe and a larger diameter pipe in accordance with an embodiment of thepresent disclosure;

FIG. 7 illustrates a robotic apparatus with wheel alignment adjusted forhelical travel along a pipe in accordance with an embodiment of thepresent disclosure;

FIG. 8A, FIG. 8B, FIG. 8C, FIG. 8D, FIG. 8E, and FIG. 8F illustrate therobotic apparatus following a helical path to pass an obstacle inaccordance with an embodiment of the present disclosure;

FIG. 9A, FIG. 9B, FIG. 9C, FIG. 9D, FIG. 9E, FIG. 9F, FIG. 9G, FIG. 9Hillustrate the robotic apparatus passing an obstacle in accordance withan embodiment of the present disclosure;

FIG. 10A, FIG. 10B, and FIG. 10C depict a fail-safe mechanism inaccordance with an embodiment of the present disclosure;

FIG. 11A, FIG. 11B, FIG. 11C, and FIG. 11D illustrate a fail-safemechanism allowing passage of an obstacle in accordance with anembodiment of the present disclosure;

FIG. 12A, FIG. 12B, FIG. 12C, and FIG. 12D illustrate the roboticapparatus navigating a bend in a pipe in accordance with an embodimentof the present disclosure;

FIG. 13A and FIG. 13B depict a sensor assembly in a lowered and raisedposition in accordance with an embodiment of the present disclosure;

FIG. 14A, FIG. 14B, FIG. 14C, and FIG. 14D depict another sensorassembly in accordance with an embodiment of the present disclosure;

FIG. 15A, FIG. 15B, FIG. 15C, and FIG. 15D depict a robotic apparatustranslating to account for wheel slip in accordance with an embodimentof the present disclosure;

FIG. 16 is a cutaway view of gears of a clamping mechanism in accordancewith an embodiment of the present disclosure;

FIG. 17 is a perspective view of a clamping mechanism in accordance withan embodiment of the present disclosure;

FIG. 18 is a side view of clamping mechanism in accordance with anotherembodiment of the present disclosure;

FIG. 19A depicts a robotic apparatus navigating a small protrusion froma pipe in accordance with an embodiment of the present disclosure;

FIG. 19B depicts a robotic apparatus navigating a bend in a pipe inaccordance with an embodiment of the present disclosure;

FIG. 20 and FIG. 21 depict side views of the prototype of roboticapparatus 100, with wheels 110 aligned for straight travel along pipe10, in accordance with an embodiment of the present disclosure;

FIG. 22 depicts a bottom view of the prototype of robotic apparatus 100,with the orientation of wheels 110 adjusted for helical travel alongpipe 10 in accordance with an embodiment of the present disclosure;

FIG. 23 depicts a side view of the prototype of robotic apparatus 100navigating a bend in pipe 10 in accordance with an embodiment of thepresent disclosure; and

FIG. 24 depicts a side view of the prototype of robotic apparatus 100,with open side 102 positioned for passing an obstacle protruding frompipe 10 in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to a roboticapparatus for traversing the exterior of piping systems, such as onescommonly found in chemical plants, power plants, manufacturing plants,and infrastructure. Piping systems can be complex and present variousobstacles that can make it difficult to traverse individual pipes in anefficient and effective manner. For example, as shown in FIG. 1A, FIG.1B, FIG. 1C, FIG. 1D, and FIG. 1E, representative obstacles may includesupports 11 (FIG. 1A), junctions 12 (FIG. 1B and FIG. 1C), flanges 13(FIG. 1C), valves 14 (FIG. 1C), vents or bleeders (similar to smallervalves), changes in diameter 15 (FIG. 1D), and bends 16 (FIG. 1E),amongst others. Various embodiments of the robotic apparatus may beconfigured to traverse pipes 10 and navigate such obstacles asencountered through a unique architecture and approach, as laterdescribed in more detail.

Embodiments of the present disclosure are directed to a roboticapparatus that may also traverse the exterior of other structures thatare similarly shaped, such as structural cables (e.g. on suspensionbridges), structural beams, powerlines, underwater cables and underwaterpiping systems.

Embodiments of the present disclosure may be useful in many applicationsincluding, without limitation:

-   -   Pipeline inspection using cameras, non-destructive testing (NDT        or NDI), or other sensors;    -   Inspecting equipment in the vicinity of the piping system    -   Performing maintenance on the piping system (e.g., cleaning the        external surface, removing insulation, applying a patch/clamp to        stop a leak)    -   Transporting tools or equipment along the piping system (e.g.,        facilitating installation of sensors on the pipe).

Various embodiments of the robotic apparatus may be capable oftraversing pipes arranged in any orientation (including horizontal andvertical), and pipes made of any material (e.g., steel, aluminum), eventhose with insulation about the exterior of the pipe. Insulation istypically a semi-rigid material, such as a mineral wool or calciumsilicate, protected by a thin metal jacket, such as aluminum orstainless steel.

Generally speaking, embodiments of the robotic apparatus of the presentdisclosure may attach to a pipe by applying a clamping force on opposingsides of the pipe. Various embodiments may be capable of holding astatic position on the pipe and may support its own weight on a range ofpipe sizes in any orientation (e.g., horizontal or vertical). Therobotic apparatus, in various embodiments, may be configured to drivealong a path in the longitudinal direction of the pipe, as well as alonga helical path (i.e., circumferential and longitudinal), on pipes ofvarying sizes and orientation. Such maneuvering, in combination with theability to expand or contract the clamping mechanism around the pipe,and an open-sided architecture, may allow the robotic apparatus tonavigate a variety of bends and obstacles encountered along the lengthof the pipe. A low profile of the robotic apparatus may enable it todrive along pipes in close proximity to other pipes or obstaclessituated close by, and an optional fail-safe mechanism may be includedto prevent the robotic apparatus from falling to the ground in the eventits wheels decoupled from the pipe. The robotic apparatus mayadditionally be capable of actively sensing and controlling the amountof clamping force it exerts on the pipe, thereby minimizing the riskthat its wheels slip along the pipe while ensuring that the roboticapparatus does not damage the pipe or insulation. Further, the roboticapparatus may be capable of actively sensing whether the wheels slip onthe pipe surface and actively control individual wheels to steer therobotic apparatus back to the centerline of the pipe.

In various embodiments, the robotic apparatus may be configured to carryand deploy a payload along the pipe, such as cameras (e.g. visualspectrum and IR cameras), various sensors like NDT sensors (e.g.,ultrasonic testing probes, pulsed eddy current probes, digitalradiography equipment, acoustic sensors) and lower explosive limit (LEL)sensors for the purpose of inspecting the piping system or equipment inits vicinity, and/or other payloads like tools and equipment. Therobotic apparatus, in various embodiments, may include an onboard powersupply (e.g., batteries) and operate via wireless communication with anoperator, thereby obviating the need for a power cord or tether.

High-Level Architecture

Referring now to FIG. 2, robotic apparatus 100 of the present disclosuremay generally include two or more wheel assemblies 101 configured forpositioning on opposing sides of pipe 10, and a clamping mechanism 150for adjusting the distance between the two or more wheel assemblies tosecure robotic apparatus 100 to pipe 10. One or more wheels of the twoor more wheel assemblies 101 may be powered such that robotic apparatusmay traverse along pipe 10 in a longitudinal direction. The wheels, invarious embodiments, may be reoriented to allow robotic apparatus 100 tomove along a helical path on pipe 10, and thereby position roboticapparatus 100 to pass over a particular portion(s) of pipe 10 and/oravoid an obstacle(s) extending from a surface of pipe 10, as laterdescribed in more detail.

FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D depict several views of arepresentative embodiment of robotic apparatus 100. The representativeembodiment shown includes three wheel assemblies 101 a, 101 b, 101 carranged in a triangular configuration in a common plane (“wheelengagement plane” 104), such that wheel assembly 101 a is positioned forengaging a first side of pipe 10, and wheel assemblies 101 b, 101 c arepositioned for engaging a second, opposing side of pipe 10. Clampingmechanism 150 is offset from the wheel engagement plane 104 and coupleswheel assemblies 101 a, 101 b, 101 c. As configured, wheel assemblies101 a, 101 b, 101 c may traverse along an outer portion of pipe 10,while the offset positioning of clamping mechanism 150 allows clampingmechanism 150 to travel through the air or water alongside pipe 10. Thepresent configuration provides robotic apparatus 100 with an open side102 (as best seen in FIG. 5C), situated opposite clamping mechanism 150,through which an obstacle extending from the outer surface of pipe 10may pass unobstructed, thereby allowing robotic apparatus to traversesuch obstacles on pipe 10 as later described in more detail.

Wheel Assembly 101

Still referring to FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D, each wheelassembly 101 may generally include a wheel 110 and an alignmentmechanism 120. Generally speaking, wheel 110 may be configured to engageand rotate along an outer surface of pipe 10, and alignment mechanism120 may be configured to adjust an orientation of wheel 110 and therebydefine a path to be followed by robotic apparatus as it traverses pipe10.

Wheel 110, in various embodiments, may include any rotatable bodysuitable for engaging and rotating along an outer surface of pipe 10. Tothat end, wheel 110 may generally include a rotating body with a contactsurface 112, and may be rotatably coupled with a wheel frame 114.

Wheel 110 may be of any shape and construction suitable for theaforementioned purpose such as, without limitation, disc- orcylindrical-shaped. While standard wheels may be utilized, in variousembodiments, it may be advantageous for wheel 110 to have a shapespecifically designed to accommodate, and thereby more effectivelyengage, the rounded shape of the outer surface of pipe 10. To that end,in various embodiments, contact surface 112 may be substantiallyinverted (e.g., v-shaped, hourglass shaped), with contact surface 112having a concave curvature dimensioned to conform to the rounded shapeof pipe 10. As best shown in FIG. 5C, the hourglass shape of contactsurface 112 may serve to maximize the contact area between wheel 110 andpipe 10 compared with a standard cylindrical wheel with a flat or convexcontact surface, as the hourglass shaped contact surface 112 of thepresent disclosure essentially wraps around the curvature of pipe 10,providing contact with not just the center of the pipe, but also withthe top quarters as well. By enhancing overall contact area betweenwheel 110 and pipe 10, more friction is available to securely couplerobotic apparatus 100 to pipe 10. By distributing the contact areabetween wheel 110 and pipe 10 around the circumference of the pipe,wheel 110 has a favorable lever arm to support off-axis forces, such asthe typical force from the clamping mechanism. Thus, the wheel's shapeallows robotic apparatus 100 to maintain a given circumferentialorientation on pipe 10 (e.g., upright, canted diagonally) withoutslipping upside-down on pipe 10.

Further, the hourglass shape of contact surface 112, in variousembodiments, may act to automatically center wheel 110 along alongitudinal centerline of pipe 10, as shown in FIG. 5C. As configured,wheel 110 may be less likely to disengage from pipe 10 entirely, ascontact between the inwardly sloping contact surface 112 and the roundedsurface of pipe 10 may bias wheel 110 to center itself over thelongitudinal centerline of pipe 10. This may be particularly beneficialin embodiments in which wheel assemblies 101 are arranged within acommon engagement plane 104, as shown, since such a configurationgenerally clamps on pipe 10 from two radial directions instead of threeor more radial directions were wheel assemblies 101 to be positioned inmore than two circumferential positions about pipe 10. Still further,contact surface 112 may be shaped and dimensioned such that it functionseffectively on a range of pipe sizes. The straight edges of the wheelprofile, as seen from a direction normal to the concentric axis of thewheel, may be purposefully chosen so that the angular distance betweenthe contact points with respect to the center of the pipe is constantfor any pipe size. However, the linear distance between the contactpoints increases with the pipe size in a manner such that the range ofpipe sizes on which wheel 110 is effective is limited by the total widthof wheel 110.

The shape of contact surface 112 may be especially suitable for helicalmotion around a pipe, including the helical motion that roboticapparatus 100 may exhibit. Consider the plane that includes the centralaxis of the wheel and a vector that is normal to the surface of thepipe. When the wheel is oriented to drive straight along thelongitudinal axis of the pipe the cross-section of the pipe in theaforementioned plane is a circle. When the wheel is oriented to drive atan angle with respect to the longitudinal axis of the pipe thecross-section of the pipe in the aforementioned plane is an ellipse.This effectively changes the curvature of the section of the pipe thatthe wheel is driving on, similar to how a change in pipe size changesthe pipe's curvature. Similar to how the wheel can adapt to a range ofpipe sizes, it can also adapt to a range of turning angles thateffectively change the curvature of the pipe under the wheel. Ingeneral, the contact area between the wheel and the pipe increases asthe curvature decreases. Hence, the contact area increases as the pipesize increases and as the angle between the wheel's direction of traveland the longitudinal axis of the pipe increases.

Alignment mechanism 120, in various embodiments, may include anymechanism suitable for adjusting an orientation of wheel 110, andthereby define a path to be followed by robotic apparatus as ittraverses pipe 10. In particular, alignment mechanism 120, in variousembodiments, may be configured to adjust the orientation of anassociated wheel 110 rotationally, with respect to an axis that isnormal to pipe 10, to steer robotic apparatus along pipe 10. That is,alignment mechanism 120, in various embodiments, may adjust theorientation of an associated wheel 110 about a yaw axis 103 of roboticapparatus 100 (shown in FIG. 3C, FIG. 5C, FIG. 8A, FIG. 8B, FIG. 8C,FIG. 8D, FIG. 8E, and FIG. 8F) such that wheel 110 is reorientedclockwise or counterclockwise about an axis extending normal to theunderlying surface of pipe 10. As configured, alignment mechanism 120may adjust wheel 110 orientation to traverse pipe 10 along a straightpathway (i.e., wheel 110 orientation aligned with yaw axis 103 ofrobotic apparatus 100 and longitudinal axis of pipe 10) or along ahelical pathway (i.e., yawed wheel 110 orientation, adjusted clockwiseor counterclockwise relative to an axis extending normal to theunderlying surface of pipe 10).

Referring to FIG. 4B, in an embodiment, alignment mechanism 120 mayinclude a motor 122 and a base plate 124 to which wheel frame 114 may berotatably coupled. Motor 122 may engage wheel frame 114 to rotate wheelframe relative to base plate 124, and thereby adjust an orientation ofwheel 110 relative to base plate 124. In the embodiment shown, baseplate 124 may be fixedly coupled to clamping mechanism 150, and wheel110 may be reoriented relative to robotic apparatus as a whole. Tofacilitate engagement between motor 122 and wheel frame 114, each may beprovided with gear teeth 123, 116, respectively, which may be interfacedwith one another such that rotation of motor 122 causes rotation ofwheel frame 114 about an axis normal to base plate 124. Of course, thisis merely an illustrative embodiment of a suitable mechanism foradjusting an orientation of wheels 110 of robotic apparatus 100, and oneof ordinary skill in the art will recognize other suitable alignmentmechanisms within the scope of the present disclosure.

In certain scenarios, one or more alignment mechanisms 120 may beconfigured to individually adjust the respective orientations of wheels110 by different amounts and/or in different directions. When all wheels110 are turned by the same amount in the same clockwise orcounter-clockwise direction, robotic apparatus 100 may travel along ahelical pathway. In contrast, when wheels 110 are oriented in oppositedirections, such that the wheels 110 on one side of pipe 10 turn in onedirection (e.g. clockwise) and the wheels on the opposite side of pipe10 turn in the opposite direction (e.g. counter-clockwise), roboticapparatus 100 may travel along a different pathway. In the latter case,wheels 110 may travel such that robotic apparatus 100 moves along thelongitudinal axis of pipe 10 and translates sideways with respect to thesame axis. This may be beneficial if wheels 110 slip, for example due tothe weight of robotic apparatus 100, away from the centerline of pipe10. This method for self-adjusting the position of robotic apparatus 100on the pipe is later illustrated in FIG. 15A, FIG. 15B, FIG. 15C, andFIG. 15D.

According to exemplary embodiments of the present disclosure, theangular orientation of the wheels may “lock” once axial movement ofrobotic apparatus 100 on pipe 10 commences. In this way, the desiredtravel pattern, e.g., helical travel with a 5° off-axis alignment ofwheels 110, may be maintained as robotic apparatus 100 moves along pipe10. Various locking features may be employed to detachably secure wheelframe 114 (and thus wheel 110) in the desired angular orientation, aswill be apparent to persons skilled in the art.

Wheel assembly 101, in various embodiments, may further include a motor130 for driving rotation of wheel 110. Motor 130 may include any motorsuch as, without limitation, a brushed DC motor or the like, suitablefor driving rotation of an associated wheel 110 of wheel assembly 101.

As shown in FIG. 3A, FIG. 3B, and FIG. 3C, in various embodiments, motor130 may be positioned external to wheel 110 and connected thereto via atraditional drive train for rotating wheel 110. Motor 130, in otherembodiments, may instead be packaged within wheel 110, as shown in FIG.4A and FIG. 4B. In particular, motor 130 may be placed inside wheel 110with its output shaft 132 concentric to the rotation axis 131 of wheel110, as shown. Motor 130 may be rigidly mounted to a cylindrical housing134, which is designed to attach to wheel frame 114. As configured,cylindrical housing 134 may act as a shaft that supports wheel 110through a set of bearings (e.g. tapered roller bearings) 136 whileallowing wheel 110 to rotate with respect to cylindrical housing 134.Output shaft 132 of motor 130 may be coupled to wheel 110, as shown, sothat motor 130 can control the rotation of wheel 110. Output shaft 132of motor 130, in various embodiments, may also be favorably supported bywheel frame 114 through an additional bearing (e.g. roller bearing) 138.

Wheel assembly 101 may further include one or more controllers (notshown) for controlling operation of motor(s) 130, such as rotationalspeed, torque, and the like. The controllers may receive commands fromvarious locations. For example, one of the controllers mounted withrespect to robotic apparatus 100 may function as a “master” controller,and the other controllers may function as “slave” controllers, such thatthe slave controllers respond to commands received from the mastercontroller. Alternatively, each of the controllers may operateindependently and may receive independent commands. The commands may beremotely transmitted, e.g., by wireless (or wired) communication, as isknown in the art. The commands may also be pre-programmed, in whole orin part, in the controller(s), e.g., time-based commands to operateaccording to clock-based criteria.

Although exemplary robotic apparatus 100 is depicted with three motors130, the disclosed apparatus may be implemented such that a motor isprovided for less than all wheels associated with the apparatus. Forexample, a single drive motor 130 associated with a single wheel 110 maybe provided, and the other wheels 110 may rotate in response to movementthat is initiated by the single motor 130 (and associated wheel 110).Similarly, a pair of motors 130 may be provided for an apparatus thatincludes three wheels 110, such that two wheels 110 may receive driveforce from associated motors 130, while the third wheel 110 rotates inresponse to movement of the apparatus relative to the pipe 10.

In exemplary embodiments of the present disclosure, the relative speedof the individual wheels 110 may be controlled so as to enhance theoperation of the apparatus. For example, it may be desired to drive thecenter wheel (e.g., that of wheel assembly 101 a) faster than either ofthe outer wheels (e.g., those of wheel assemblies 101 b, 101 c) whennavigating a turn or bend in the pipe 10. In such circumstance, thecontrollers may be programmed to increase the drive force to the centerwheel 110 and/or reduce the drive force to outer wheel(s) 110.Alternatively, it may be desirable to drive the outer wheels 110 fasterthan the center wheel 110 when navigating a turn or bend in the pipe 10.In such circumstance, the controllers may be programmed to increase thedrive force to the outer wheel(s) 110 and/or reduce the drive force tothe center wheel 110. The noted adjustments may be initiated manually,e.g., by an operator, or may be initiated automatically, e.g., based onsensing mechanism(s) associated with the assembly that identify aturn/bend in the pipe 10 (e.g., based on sensing of the angularorientation of one or more aspects of the apparatus).

Clamping Mechanism 150

Referring ahead to FIG. 5A, FIG. 5B, and FIG. 5C, clamping mechanism 150of robotic apparatus 100, in various embodiments, may generally includeone or more arm members 152 and one or more biasing members 154. Armmember(s) 152, in various embodiments, may connect wheel assemblies 101on opposing sides of pipe, and biasing member(s) 154 may apply a pullingor pushing force on arm members 152 that causes the wheel assemblies toengage the opposing sides of pipe 10, thereby securing robotic apparatus100 to pipe 10 as later described in more detail.

Arm members 152, in various embodiments, may be arranged in pairs, withthe members of a given pair arranged parallel to one another andseparated by a gap, as shown in FIG. 5A. The ends of each member 152 ina given pair may be rotatably coupled with the associated wheelassemblies 101 such that the given pair forms a parallelogram-shapedlinkage between the corresponding wheel assemblies 101. Theparallelogram-shaped linkage, in an embodiment, may act to keep theconnected wheel assemblies 101 in parallel alignment with one another oneither side of pipe 10 regardless of the relative positions of theconnected wheel assemblies 101 (which may change with pipe diameter, aslater described). By keeping the connected wheel assemblies 101 inparallel alignment with one another on opposing sides of pipe 10, theassociated wheels 110 may more effectively engage the surface of pipe 10and securely couple robotic apparatus 100 thereto. Additionally, keepingthe connected wheel assemblies 101 in parallel alignment with oneanother is important for the alignment mechanism 120 to functionproperly. That is, yaw axis 103 about which alignment mechanism 120turns wheel 110 should be normal to the surface of pipe 10.

For example, in FIG. 5A, arm members 152 a, 152 b form a pair with theaforementioned arrangement, and connect wheel assembly 101 a with wheelassembly 101 b. As configured, wheel assembly 101 b may pivot clockwise(e.g., up and to the left) relative to wheel assembly 101 a to engage anarrow diameter pipe 10, or may pivot counterclockwise (e.g., down andto the right) relative to wheel assembly 101 a to engage a largerdiameter pipe, and vice versa. As wheel assemblies 101 a, 101 b pivotrelative to one another, the parallelogram-shaped linkage formed by armmembers 152 a, 152 b causes the connected wheel assemblies 101 a, 101 bto remain in parallel alignment with one another on either side of pipe10, thereby ensuring that wheel 110 of each remains flush and engagedwith pipe 10. Similarly, arm members 152 c, 152 d form a pair with theaforementioned arrangement, and connect wheel assembly 101 a with wheelassembly 101 c. As configured, wheel assembly 101 c may pivotcounterclockwise (e.g., up and to the right) relative to wheel assembly101 a to engage a narrow diameter pipe 10, or may pivot clockwise (e.g.,down and to the left) relative to wheel assembly 101 a to engage alarger diameter pipe, and vice versa. As wheel assemblies 101 a, 101 cpivot relative to one another, the parallelogram-shaped linkage formedby arm members 152 b, 152 c causes the connected wheel assemblies 101 a,101 c to remain in parallel alignment with one another on either side ofpipe 10, thereby ensuring that wheel 110 of each remains flush andengaged with pipe 10.

Of course, in various embodiments, a single arm member 152 (as opposedto the aforementioned pairs) may be used connect two wheel assemblies101. In such embodiments (not shown), alternative approaches may beemployed to maintain the connected wheel assemblies 101 in parallelalignment, if desired. For example, a single arm member 152 may be usedwith a pair of wires in the same plane as the aforementioned pairs. Thewires may attach directly to wheel assemblies 101 on each side of armmember 152. While arm member 152 would provide the necessary structuralintegrity, the wires would engage when arm member 152 pivoted and (basedon the same kinematics as the parallelogram-shaped linkage) keep theconnected wheel assemblies 101 in parallel alignment with one another.It should be recognized that two wires may be be needed since wirestypically only carry loads in tension, not compression.

Biasing members 154, in various embodiments, may be configured to applya force for pulling opposing wheel assemblies 101 toward opposing sidesof pipe 10 to secure robotic apparatus 100 to pipe 10. Biasing members154 may include any mechanism suitable for this purpose such as, withoutlimitation, a gas tension spring (shown in FIG. 5A, FIG. 5B, and FIG.5C), tension springs (shown in FIG. 17), compression springs, torsionsprings, or any combination thereof. Additionally or alternatively,biasing mechanisms 154 may include one or more active biasing members(as opposed to the immediately aforementioned passive biasing members)such as a motorized pulley system, motorized lead screw, or apneumatic/hydraulic actuator, or the like.

Clamping mechanism 150 as configured may automatically adjust thepositions of wheel assemblies 101 relative to one another to accommodatepipes of varying diameters. For example, robotic apparatus 100 maycompress significantly to accommodate small diameter pipes, resulting ina configuration in which wheel assemblies 101 b, 101 c are nearlycoplanar with wheel assembly 101 a along a longitudinal axis of pipe 10(i.e., separated by the small diameter of pipe 10), but are situated faraway from wheel assembly 101 a along a longitudinal axis of pipe 10, asshown in FIG. 6A. Conversely, robotic apparatus 100 may expandsignificantly to accommodate large diameter pipes, resulting in aconfiguration in which wheel assemblies 101 a, 101 b, 101 c are situatedclose to one another along a longitudinal axis of pipe 10, but wheelassembly 101 a is situated far from wheel assemblies 101 b, 101 c (i.e.,separated by the large diameter of pipe 10) , as shown in FIG. 6B.Biasing members 154 a, 154 b, 154 c, 154 d, as configured, maycontinuously apply the pulling force between wheel assembly 101 a andeach of wheel assemblies 101 b, 101 c, thereby securely coupling (or“clamping”) robotic apparatus 100 to pipe 10, regardless of itsorientation about the circumference of pipe 10 and regardless of whetherpipe 10 is oriented horizontally or vertically.

Referring back to FIG. 5A, FIG. 5B, and FIG. 5C, in a representativeembodiment, biasing mechanism 154 may include a gas tension spring. Asshown, the gas tension spring may couple the one or more arms 152extending from wheel assemblies 101 b, 101 c to wheel assembly 101 a. Asthe gas tension spring exerts a pulling force on the arm members 152 itcreates a torque about the pivot points where the arm members 152 attachto the wheel assembly 101 a. This torque will act to pull wheelassemblies 101 b, 101 c outwards and upwards relative to wheel assembly101 a, causing robotic apparatus 100 to compress onto pipe 10.

Referring ahead to FIG. 16, in an embodiment, clamping mechanism 150 mayinclude a set of gears that attach to the axles that connect the armmembers 152 b, 152 d to the wheel assembly 101 a. These gears areincluded to ensure that the arm members 152 a, 152 b, 152 c, 152 d pivotby the same angular displacement and the clamping mechanism 150 remainssymmetrical with respect to wheel assembly 101 a. The arm members 152need to pivot by the same angular displacement so that the connectedwheel assemblies 101 are not only in parallel alignment with respect toeach other, but also with respect to pipe 10. In the alternativeembodiment of FIG. 17 (later described), a specific mechanism is notneeded to ensure that the member arms pivot equally. That is, if equalbiasing members 154 connect the 101 a wheel assembly to each of the setsof arm members 152 (in contrast to one biasing member that connects thearm members 152 directly to each other, as shown in FIG. 5A, FIG. 5B,and FIG. 5C) they will turn the arm members 152 by the same angulardisplacement since that is the energetically most favorable position.

In an alternative embodiment the biasing member(s) is an activelycontrolled actuator, such as a linear actuator (lead/ball/roller screw),rack-and-pinion, worm drive, or hydraulic/pneumatic actuator. Theadvantages of an actively controlled biasing member include the lowerlikelihood of exerting a force that is too small or too large. If theclamping force is too small the wheels will start to slip on the pipe.If the clamping force is too large it places unnecessary stress on theclamping mechanism and it increases the risk of deforming and/ordamaging the pipe, the pipe insulation, or other equipment. With anactively controlled biasing member the force exerted can be adjusted inreal time based on sensor values (e.g. wheel slip sensors), based onenvironmental conditions (e.g. higher clamping force is needed if rainmakes the pipes slippery), and/or visual observations from the operator(e.g. lower clamping force is recommended if insulation deformation isobserved). An actively controlled biasing member can also facilitate theprocess of attaching and detaching the robotic apparatus to the pipe,while a passive biasing member necessitates the use of a clamp orsimilar device to attach and detach the apparatus to the pipe. Anactively controlled biasing member can also be designed to exert theappropriate force on a wide range of pipe sizes, while a passive biasingmember usually has a more limited range of pipe sizes on which it exertsthe appropriate amount of force. The two main disadvantages of anactively controlled biasing member are the following. Firstly, activelycontrolled actuators typically don't move as fast as passive biasingmembers. When the robotic apparatus drives around a bend it isespecially important to be able to close the clamping mechanism quicklyto maintain contact between the wheels and the pipe. Secondly, activelycontrolled apparatuses are mechanically and electronically more complex,and are therefore more prone to failure.

Referring ahead to FIG. 17, in another alternative embodiment, one ormore biasing members 154 may connect a wheel assembly 101 situated on afirst side of pipe 10 with arm member(s) 152 extending to a wheelassembly 101 situated on a second, opposing side of pipe 10, as shown.Of course, in various embodiments, biasing members 154 may additionallyor alternatively connect opposing wheel assemblies directly (or evenassociated structure) to similar effect. For example, in the embodimentof FIG. 17, biasing members 154 a, 154 b (shown here as tension springs)may connect wheel assembly 101 a to arm members 152 a, 152 b extendingto wheel assembly 101 b, and biasing members 154 c, 154 d may connectwheel assembly 101 a to arm members 152 c, 152 d extending to wheelassembly 101 c. More specifically, first ends of biasing members 154 a,154 b, 154 c, 154 d each connect to a strut 156 extending longitudinallyfrom wheel assembly 101 a, and second ends of biasing members 154 a, 154b, 154 c, 154 d each connect to a mid or distal portion of arm members152 a, 152 b, 152 c, 152 d, respectively. Such an arrangement ensuresthat the vectors of the associated pulling force generated by biasingmembers 154 a, 154 b and biasing members 154 c, 154 d will act to pullwheel assemblies 101 b, 101 c, respectively, outwards and upwardsrelative to wheel assembly 101 a (while simultaneously pulling wheelassembly 101 a downwards), causing robotic apparatus 100 to compressonto pipe 10 as shown in FIG. 17.

FIG. 18 illustrates yet another alternative embodiment of clampingmechanism 150. While this embodiment of clamping mechanism 150 is shownon a four-wheeled robotic apparatus 100, one of ordinary skill in theart will recognize that the present embodiment may be adapted to roboticapparatuses 100 having three wheels or greater than four wheels withoutdiverging from the scope of the present disclosure.

In this embodiment, clamping mechanism 150 may generally include a motor180 for driving a lead screw 181, which in turn moves a plurality oflinear arm pairs 182 a, 182 b, 182 c to expand or compress clampingmechanism 150. More specifically, wheel assemblies 101 a and 101 b maybe coupled to a first frame 183 a, thereby defining a first frameassembly 184 a, and wheel assemblies 101 c, 101 d may be coupled to asecond frame 183 b, thereby defining a second frame assembly 184 b. Eachof the linear arms 182 may have a first end 185 rotatably coupled toeither the first frame 183 a or the second frame 183 b, and a second end186 rotatably and slidably coupled to a linear guide 187, as shown.Second ends 186 of at least some of the plurality of linear arms 182 maybe operably coupled to lead screw 181 such that rotation of lead screw181 causes the operably coupled second ends 186 to move from a firstposition on linear guide 187 to a second position on linear guide 187,thereby changing the angle of each of the linear arms 182 in each pairrelative to one another. As the angle between of linear arm 182 of eachpair changes, the distance between first frame assembly 184 a and secondframe assembly 184 b is adjusted. For example, driving lead screw 181 ina first direction may cause the operably coupled second ends 186 to moveinwards along linear guide 187, causing the angle between the lineararms 182 of each pair to increase as each arm 182 becomes moreperpendicular to linear guide 187. This may cause first frame assembly184 a and second frame assembly 184 b to move further away from linearguide 187, thereby expanding robotic apparatus 100. Conversely, drivinglead screw 181 in a second, opposing direction may cause the operablycoupled second ends 186 to move outwards along linear guide 187, causingthe angle between the linear arms 182 of each pair to decrease as eacharm 182 becomes more parallel to linear guide 187. This may cause firstframe assembly 184 a and second frame assembly 184 b to move closer tolinear guide 187, thereby compressing robotic apparatus 100. Byadjusting the distance between the first frame assembly 184 a and thesecond frame assembly 184 b, clamping mechanism 150 can accommodatevarious diameter pipes 10 and navigate bends as shown in FIG. 19B anddescribed throughout the present disclosure.

Referring now to FIG. 19A, additionally or alternatively, in anembodiment, less than all of second ends 186 may be operativelyconnected to lead screw 181. As configured, those second ends 182 notoperatively connected to lead screw 181 may freely translate alonglinear guide 187 and thereby allow at least one of first assembly 184 aand second assembly 184 b to pivot relative to one another. This, inturn, may allow robotic apparatus to traverse small obstacles protrudingfrom the pipe while maintaining all but one wheel 110 in contact withthe surface of pipe 10 at all times. For example, still referring toFIG. 19A, wheel assembly 101 c may climb the small protruding obstacle,causing second frame assembly 184 b to pivot. This pivoting of secondframe assembly 184 b allows wheel assembly 101 d to remain in contactwith the underside of pipe 10. Further, the pivoting of second frameassembly 184 b relative to first frame assembly 184 a also allows wheelassemblies 101 a, 101 b to remain in contact with the upper side of pipe10 while wheel assembly 101 c traverses the obstacle. Similarly, frameassemblies 184 a, 184 b will pivot relative to one another as wheelassembly 101 d subsequently traverses the obstacle and thus wheelassemblies 101 a, 101 b, and 101 c will remain in contact with pipe 10.

Traversing Pipeline and Avoiding Obstacles

In operation, robotic apparatus 100 may be mounted on an exteriorsurface of pipe 10 and traverse pipe 10 to deliver, perform, and/orsupport various functionalities, such as inspecting pipe 10 forstructural defects or corrosion, and sampling the surroundingenvironment for traces of fluids that may have leaked from pipe 10. Indoing so, robotic apparatus 100 may at times may need to repositionitself circumferentially on pipe 10 to, for example, navigate one ormore obstacles extending from pipe 10 or to inspect a particular side(s)of pipe 10. Similarly, at times it may be advantageous for roboticapparatus to corkscrew or otherwise follow a helical pattern about theexterior of pipe 10 when attempting to inspect the majority of theexterior of pipe 10 or the surrounding environment. Accordingly, roboticapparatus 100 of the present disclosure may be configured to traversepipe 10 along straight and helical paths. Generally speaking, travelalong these paths may be accomplished by driving one or more of wheels110 using motor(s) 130 and steering wheels 110 using alignmentmechanisms 120, as further described in more detail below.

To follow a straight path along pipe 10, alignment mechanisms 120 mayorient wheels 110 to be aligned with the longitudinal axis of pipe, asshown in FIG. 5A, FIG. 5B and FIG. 5C. As configured, the hourglassshape (if equipped) may center wheels 110 on opposing sides of pipe 10and steer robotic apparatus along a straight path such that wheels 110continue following those particular opposing sides (e.g., the top andbottom of pipe 10 as shown).

Referring now to FIG. 7, FIG. 8A, FIG. 8B, FIG. 8C, FIG. 8D, FIG. 8E,and FIG. 8F, to follow a helical path, whether for the purposes offollowing a helical inspection pattern or simply to reposition roboticapparatus about the circumference of pipe 10, alignment mechanisms 120may adjust the orientation of wheels 110 rotationally relative to yawaxis 103 of robotic apparatus 100, which in the present embodimentcoincides with engagement plane 104. Alignment mechanisms 120, invarious embodiments, may adjust the orientation of wheels 110rotationally (i.e., clockwise or counter-clockwise). For example, in anembodiment, alignment mechanism 120 may adjust the orientation of wheels110 to the left to guide robotic apparatus 100 along a helical path withcoils moving in a counterclockwise direction about the circumference ofpipe 10. Likewise, alignment mechanism 120 may adjust the orientation ofwheels 110 to the right to guide robotic apparatus 100 along a helicalpath with coils moving in a clockwise direction about the circumferenceof pipe 10.

Alignment mechanisms 120, in various embodiments, may also adjust theorientation of wheels 110 to any suitable degree to control a pitch ofthe resulting helical path. For example, adjusting the orientation ofwheels 110 to the left or right by a small amount (e.g., 5 degrees) maycause the resulting helical pathway to have a large pitch (i.e., largedistance between adjacent coils), while adjusting the orientation ofwheels 110 to the left or right by a large amount (e.g., 30 degrees) maycause the resulting helical pathway to have a small pitch (i.e., smalldistance between adjacent coils). Alignment mechanism 120, in variousembodiments, may be configured to adjust the orientation of wheels 110by up to 89 degrees relative to a longitudinal axis of pipe 10 and stillfollow a helical pattern; however, alignment mechanism 120 may morepreferably be configured to adjust the orientation of wheels 110 fromcenter by between about 1 degree and about 60 degrees. The greater theangle to which the wheels 110 are turned, the further apart the contactareas move on the wheel surface 112. In other words, if the wheel 110 isto stay in contact with the pipe 10 (and not only contact along theouter rims of the wheels 110) the total width of the wheel 110, the andthe diameter of the pipe 10 put an upper limit on the angle to which thewheel 110 can be turned.

Referring now to FIG. 9A, FIG. 9B, FIG. 9C, FIG. 9D, FIG. 9E, FIG. 9F,FIG. 9G, FIG. 9H, FIG. 10A, FIG. 10B, FIG. 10C, FIG. 11A, FIG. 11B, FIG.11C, FIG. 11D, FIG. 12A, FIG. 12B, FIG. 12C, and FIG. 12D, roboticapparatus 100, in various embodiments, may be repositioned about thecircumference of pipe 10 to navigate past various obstacles, asdescribed in more detail below.

FIG. 9A, FIG. 9B, FIG. 9C, FIG. 9D, FIG. 9E, FIG. 9F, FIG. 9G, and FIG.9H illustrate a representative approach for navigating a largeunidirectional protrusion from pipe 10 such as pipe junctions and pipesupports using robotic apparatus 100. In FIG. 9A robotic apparatus 100approached a large protruding obstacle. Its orientation is not suitableto pass the obstacle and it will go through the procedure to rotate to asuitable orientation for passing the obstacle. In FIG. 9B the robot hasturned its wheels in place (to about 45 degrees) using the alignmentmechanism that was described earlier in this disclosure. It turns thewheels so that it can commence the helical movement needed to change itsorientation with respect to the pipe. In FIG. 9C it is starting totravel in a helical pathway along the pipe with the wheels kept at thesame angle as in FIG. 9B. FIG. 9D shows the robot as it keeps driving ina helical pathway. It drives along the longitudinal axis and around thecircumference of the pipe at the same time. In FIG. 9E the robot hasreach the preferred orientation with respect to the obstacle. The openside of the robot is on the same side of the pipe as the obstacle. FIG.9F shows how the robot employs the alignment mechanism to turn thewheels back to the default position, where the direction of travel isparallel with the longitudinal axis of the pipe. Once it is in thepreferred orientation the robot keeps driving straight to pass theobstacle. FIG. 9G shows the robot as it starts to pass the obstacle andthe obstacle protrudes through the open side of the robot. FIG. 9H showshow the robot has passed the obstacle and it returns to its normaloperation.

FIG. 10A, FIG. 10B, and FIG. 10C depict various views of a mechanism 160for preventing robotic apparatus 100 from falling off of pipe 10 shouldrobotic apparatus 100 decoupled from pipe 10. Also referred to herein asa “fail-safe mechanism”, mechanism 160 may extend from one or more ofwheel assemblies 101 and across open side 102 of robotic apparatus 100,such that robotic apparatus 100 effectively surrounds pipe 10 on allsides as shown in FIG. 11A, FIG. 11B, FIG. 11C, and FIG. 11D. Asconfigured, should wheels 110 slip or otherwise disengage from pipe 10,robotic apparatus 100 will remain connected to pipe 10 in a manner thatprevents it from falling to the ground and being damaged or destroyed.

Referring first to FIG. 10A, mechanism 160 may generally comprise an armmember 162 and a rotating joint 164. In various embodiments, rotatingjoint 164 forms a proximal portion of fail-safe mechanism 160, and iscoupled to or forms part of wheel assembly 101. Arm member 162 may becoupled to or be integrally formed as part of rotating joint 164, andmay extend across open side 102 of robotic apparatus 100 in a neutralstate. To allow for a large protrusion or other obstacle to pass throughopen side 102 of robotic apparatus 100, rotating joint 164 may beconfigured to rotate within the plane of open side 102 in response toforces applied to arm member 162 by the obstacle as robotic apparatustraverses a corresponding section of pipe 10. Stated otherwise, uponcoming into contact with the obstacle, arm member 162 may passivelysweep rearwards about a pivot point defined by rotating joint 164 untilthe obstacle has passed beyond the reach of arm member 162, as shown inFIG. 10B. Upon clearing the obstacle, arm member 162 may automaticallysweep forward to return to the neutral state, where it again extendsacross open side 102 to prevent robotic apparatus 100 from fallingshould wheels 110 decouple from pipe 10.

To that end, rotating joint 164, in various embodiments, may include abiasing mechanism 166, such as torsion spring or othermechanism/assembly configured to apply a restorative force for returningarm member 162 to the neutral state after an obstacle is passed. In theembodiment shown in FIG. 10C, biasing mechanism 166 includes an assemblyof linear springs 167 a, 167 b connected to a pulley assembly 168. Inparticular, springs 167 a, 167 b may be the same or substantiallysimilar to one another, and may be arranged side-by-side and extend froma proximal end of fail-safe mechanism 160 towards pulley assembly 168.Pulley assembly 168 may include a pulley connected to springs 167 a, 167b by a cable, wire, string, or other such connector (collectively,“cable” hereinafter). A first end 168 a of the cable may extend axiallythrough spring 167 a and connect to a cap 169 a positioned at a proximalend of spring 167 a, and likewise a second end 168 b of the cable mayextend axially through spring 167 b and connect to a cap 169 bpositioned at a proximal end of spring 167 b. As configured, when armmember 162 (and by extension pulley 169), is swept clockwise thisfigure, pulley assembly 168 may pull cable end 168 b (and attached cap169 b ) downwards, thereby progressively compressing spring 167 b. Thisin turn builds up a restoring force in spring 167 b that generates acounterclockwise moment for sweeping arm member 162 counterclockwise inthis figure back to the neutral state when the obstacle has cleared armmember 162. Likewise, when arm member 162 (and by extension pulleyassembly 168), is swept counterclockwise in this figure, pulley assembly168 may pull cable end 168 a (and attached cap 169 a) downwards, therebyprogressively compressing spring 167 a. This in turn builds up arestoring force in spring 167 a that generates a clockwise moment forsweeping arm member 162 clockwise in this figure back to the neutralstate when the obstacle has cleared arm member 162.

Notably, rotating joint 164, in various embodiments, may be constrainedto rotation within the plane of open side 102 only, and thus notpermitted to rotate transverse to (e.g., away from or towards pipe 10)said plane, such that fail-safe mechanism 160 does not permit pipe 10 topass through open side 102 in the event robotic apparatus 100 were todecouple from pipe 10.

FIG. 11A, FIG. 11B, FIG. 11C, and FIG. 11D illustrate a representativeapproach for navigating a large unidirectional protrusion from pipe 10such as pipe junctions and pipe supports when robotic apparatus 100 isequipped with fail-safe mechanism 160. FIG. 11A shows robotic apparatus100 as it approaches an obstacle protruding from pipe 10. In thisfigure, robotic apparatus 100 is already in the preferred orientationfor passing the protruding obstacle—that is, open side 102 is alignedwith the protruding obstacle. It drives straight ahead, parallel to thelongitudinal axis of the pipe. In FIG. 11B, robotic apparatus 100 startsto pass the obstacle and the failsafe mechanism 160 a attached to thefirst wheel assembly has hit the protrusion. Since arm member 162 isfree to rotate in this plane it starts to pivot as it gets pushed by theprotruding obstacle. In FIG. 11C, the first failsafe mechanism 160 hascompletely passed the obstacle and biasing member 166 has returned armmember 162 to its neutral state. The middle failsafe mechanism 160 b isnow passing the protruding obstacle. FIG. 11D shows how the middlefailsafe mechanism 160 b has cleared the obstacle and returned to itsneutral position. The last failsafe mechanism 160 c is now contactingthe protruding obstacle. Once the last wheel assembly passes theobstacle the last failsafe mechanism 160 c will swing back to theneutral safe position and robotic apparatus 100 is free to return to itsnormal operation.

FIG. 12A, FIG. 12B, FIG. 12C, and FIG. 12D illustrate a representativeapproach for navigating a bend or curve in pipe 10 using roboticapparatus 100. FIG. 12A shows the ideal orientation of the roboticapparatus 100 as it approaches the bend. The depicted embodiment ofrobotic apparatus 100 is designed to traverse the bend with the singlewheel assembly 101 a driving along the outer centerline of the bend andthe two wheel assemblies 101 b, 101 c on the opposing side to drivealong the inner centerline of the bend. Alternative embodiments havebeen designed so that the single wheel assembly 101 a can drive alongthe inside of the bend and the two wheel assemblies 101 b, 101 c candrive along the outside of the bend. However, these two differentapproaches place different constraints on the range of motion of theclamping mechanism 150, and a single embodiment is typically designed toemploy one of the two approaches. FIG. 12B shows how the roboticapparatus 100 enters the bend. As shown, robotic apparatus 100 has toexpand significantly as it drives towards the apex of the bend. Theoutside wheel in wheel assembly 101 a will speed up as it enters thebend to compensate for the longer path length compared to the otherwheels. In FIG. 12C, robotic apparatus 100 has passed the apex of thebend. At this stage clamping mechanism 150 gradually contracts to keepthe wheels 110 in contact with the surface of the pipe 10 and theoutside wheel 110 a gradually returns to the same speed as the otherwheels 110 b, 110 c, as the path length difference diminishes. In FIG.12D, robotic apparatus 100 has completely passed the bend and it returnsto its normal operation.

Pipeline Inspection and Other Payloads

FIG. 13A and FIG. 13B illustrate an embodiment of robotic apparatus 100including a sensor assembly 170 for performing structural inspections ofpipe 10. Sensor assembly 170, in various embodiments, may generallyinclude one or more arms 172 and an actuator 174 for positioning asensor 176 relative to pipe 10.

Sensor 176, in various embodiments, may include one of a variety ofsensors suitable for inspecting or otherwise gathering informationconcerning pipe 10 and/or the surrounding environment. For example, inan embodiment, sensor 176 may include an ultrasonic sensor or othersensor suitable for non-destructive inspection (NDI) of structuralaspects of pipe 10, such as measuring wall thickness or detectingcracks/corrosion. In another embodiment, sensor 176 may include a sensorconfigured to sample air proximate to pipe 10 for traces of fluids(e.g., natural gas, oil) that may have leaked out of pipe 10. Suchtraces may be indicative of cracks or corrosion in pipe 10, and thus maybe used for structural inspection purposes. While sensor assembly 170 ofthe present disclosure may be described in the context of positioning asensor 176 for pipeline inspection purposes, it should be recognizedthat any sensor 170 may be used in connection with sensor assembly 170for any suitable purpose.

Arm(s) 172, in various embodiments, may couple sensor 176 to roboticapparatus 100 and be moved to position sensor 176 relative to pipe 10.In particular, a first end of arm(s) 172 may be rotatably coupled torobotic apparatus 100, for example, on strut 156 as shown. Asconfigured, arm(s) 172 may be pivoted up and down on strut 156 andthereby position sensor 176 away from or close to pipe 10, respectively.In an embodiment (shown), the second end of arm(s) 172 may also berotatably coupled to sensor 176, thereby allowing sensor 176 to pivotrelative to arm(s) 172 and thus remain parallel to the surface of pipe10 if desired or necessary for sensor 176 to function optimally. FIG.13A illustrates sensor assembly 170 in a raised position and FIG. 13Billustrates sensor assembly in a lowered position. Arm(s) 172, in anembodiment, may be used to raise sensor 176 to a position away from pipe10 when measurements are not needed and/or to prevent sensor 176 fromcolliding with an obstacle along pipe 10. Conversely, arm(s) 172, in anembodiment, may be used to lower sensor 176 to a position close to oragainst pipe 10 for taking measurements.

Actuator 174, in various embodiments, may be used to move arm(s) 172 inpositioning sensor 176. Actuator 174 may include any actuator, motor,and associated assemblies (e.g., pulleys, gear trains). In the exemplaryembodiment shown, actuator 174 includes a linear actuator having aproximal end rotatably coupled to wheel assembly 101 a of roboticapparatus 100 and having a distal end coupled to arm(s) 172, andspecifically here to a cross-bar member extending between arms 172 thatfreely rotates to maintain alignment with linear actuator 172, as shown,regardless of whether linear actuator 172 is in an extended or retractedposition. Of course, one of ordinary skill in the art will recognizealternative actuators that may be suitable for the described purposewithin the scope of the present disclosure. For example, in anotherembodiment (not shown), actuator 174 may include a motor configured towind in/out a cable or pulley assembly positioning arm(s) 172 and sensor176 coupled thereto.

FIG. 14A, FIG. 14B, FIG. 14C, and FIG. 14D depict another embodiment ofsensor assembly 170, which generally includes sensor 176, and anarticulated arm 190 comprising a first arm segment 192 and a second armsegment 194. A proximal end of first arm segment 192 may be rotatablycoupled by a first rotating joint 193 to robotic apparatus 100 such thatarticulated arm 190 may be rotated relative to robotic apparatus 100. Aproximal end of second arm segment 194 may be rotatably coupled by asecond rotating joint 195 to a distal end of first arm segment 192 suchthat second arm segment 194 may be rotated relative to first arm segment192. Each rotating joint 193, 195, in various embodiments, may bemotorized and configured for independent rotation from one another. Asconfigured, first rotating joint 193 may raise or lower articulated arm190 relative to pipe 10 and second rotating joint 195 may independentlyadjust an orientation of sensor 176 relative to the surface of pipe 10,as shown in FIG. 14A and FIG. 14C.

Further, first rotating joint 193 may be rotated to a greater extent forpositioning articulated arm 190 out in front of either end of roboticapparatus 100, as shown in FIG. 14B and FIG. 14D. As configured, sensor176 may be positioned to take measurements in front of robotic apparatus100 regardless of its direction of travel on pipe 10. In one aspect,this configuration may provide for more accurate measurements, asrobotic apparatus 100 would not yet be in contact with the portion ofpipe 10 being inspected with sensor 176, which may otherwise producevibrations, cause a dampening effect, or otherwise affect structuralproperties of the portion of pipe 10 being inspected. In another aspect,by positioning sensor assembly out in front of robotic apparatus 100(again, regardless of the direction of travel), it may be possible toinspect portions of pipe 10 all the way up to an upcoming obstacle.Contrast this with only being able to inspect only those portions ofpipe 10 more than a length of robotic apparatus away from the upcomingobstacle because sensor assembly 170 is positioned behind roboticapparatus 100.

FIG. 20, FIG. 21, FIG. 22, FIG. 23, and FIG. 24 are photographs of aprototype of a representative embodiment of robotic apparatus 100 forfurther illustrative purposes. FIGS. 20 and 21 depict side views of theprototype of robotic apparatus 100, with wheels 110 aligned for straighttravel along pipe 10. FIG. 22 depicts a bottom view of the prototype ofrobotic apparatus 100, with the orientation of wheels 110 adjusted forhelical travel along pipe 10. FIG. 23 depicts a side view of theprototype of robotic apparatus 100 navigating a bend in pipe 10. FIG. 24depicts a side view of the prototype of robotic apparatus 100, with openside 102 positioned for passing an obstacle protruding from pipe 10.

Although the present disclosure and its advantages have been describedin detail, it should be understood that various changes, substitutionsand alterations can be made herein without departing from the spirit andscope of the disclosure as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure, processes, machines, manufacture, compositions of matter,means, methods, or steps, presently existing or later to be developedthat perform substantially the same function or achieve substantiallythe same result as the corresponding embodiments described herein may beutilized according to the present disclosure. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.

What is claimed is:
 1. A robotic apparatus, comprising: a first wheel, asecond wheel, and a third wheel, each configured for positioning on anouter surface of a pipe such that: (i) the first wheel is situated on afirst side of the pipe, (ii) the second wheel and the third wheel aresituated on a second, opposing side of the pipe, and (iii) the firstwheel, the second wheel, and the third wheel are situated at differentlongitudinal locations along a length of the pipe; and a clampingmechanism configured to apply a force for urging the first wheel, thesecond wheel, and the third wheel towards a central axis of the pipe. 2.The robotic apparatus of claim 1, wherein the first wheel, the secondwheel, and the third wheel are arranged in a common plane with oneanother.
 3. The robotic apparatus of claim 1, wherein the clampingmechanism includes a first arm connecting the first wheel with thesecond wheel and a second arm connecting the first wheel with the thirdwheel.
 4. The robotic apparatus of claim 1, wherein the clampingmechanism includes an active biasing member for applying the forcetowards the central axis of the pipe.
 5. The robotic apparatus of claim4, wherein the active biasing member includes a gas spring, a mechanicalspring, an electric actuator, or a pneumatic actuator.
 6. The roboticapparatus of claim 1, wherein the force urges the second wheel and thethird wheel to pivot outwards in opposing directions about the firstwheel.
 7. The robotic apparatus of claim 1, further comprising analignment mechanism associated with at least one of the first wheel, thesecond wheel, and the third wheel, wherein the alignment mechanism(s) isconfigured for selectably adjusting an orientation of the associatedwheel.
 8. The robotic apparatus of claim 2, wherein the clampingmechanism is offset from and parallel to the common plane shared by thewheels.
 9. The robotic apparatus of claim 8, further comprising an openside situated opposite the clamping mechanism, through which an obstacleextending from the pipe may pass unobstructed.
 10. The robotic apparatusof claim 9, further including one or more members configured to extendacross the open side of the robotic apparatus to prevent the roboticapparatus from falling off the pipe.
 11. A robotic apparatus,comprising: a first wheel configured for positioning on an outer surfaceof a pipe on a first side of a pipe; a second wheel and a third wheel,each configured for positioning on the outer surface of the pipe on asecond, opposing side of the pipe; and a clamping mechanism configuredto apply a force for urging the second wheel and the third wheel topivot outwards in opposing directions about the first wheel for securingthe first wheel, the second wheel, and the third wheel to the pipe. 12.The robotic apparatus of claim 11, wherein the first wheel, the secondwheel, and the third wheel are arranged in a common plane with oneanother.
 13. The robotic apparatus of claim 11, wherein the clampingmechanism includes a first arm connecting the first wheel with thesecond wheel and a second arm connecting the first wheel with the thirdwheel.
 14. The robotic apparatus of claim 11, wherein the clampingmechanism includes an active biasing member for applying the forcetowards the central axis of the pipe.
 15. The robotic apparatus of claim14, wherein the active biasing member includes a gas spring, amechanical spring, an electric actuator, or a pneumatic actuator. 16.The robotic apparatus of claim 11, wherein each of the first wheel, thesecond wheel, and the third wheel are configured for positioning on theouter surface of the pipe at different positions along a length of thepipe.
 17. The robotic apparatus of claim 11, further comprising analignment mechanism associated with at least one of the first wheel, thesecond wheel, and the third wheel, wherein the alignment mechanism(s) isconfigured for selectably adjusting an orientation of the associatedwheel.
 18. The robotic apparatus of claim 12, wherein the clampingmechanism is offset from and parallel to the common plane shared by thewheels.
 19. The robotic apparatus of claim 18, further comprising anopen side situated opposite the clamping mechanism, through which anobstacle extending from the pipe may pass unobstructed.
 20. The roboticapparatus of claim 19, further including one or more members configuredto extend across the open side of the robotic apparatus to prevent therobotic apparatus from falling off the pipe.